onsemi BZX84C9V1ET3G

Overview

BZX84C9V1ET3G from onsemi is a 9.1 V, 250 mW surface-mount Zener diode in SOT-23 package, designed for precision voltage regulation and reference in space-constrained circuits. It delivers ±5% tolerance at 5 mA test current, 15 Ω dynamic impedance, and operates across −65 °C to +150 °C junction temperature range. It is used in voltage clamping, overvoltage protection, and low-power biasing in portable electronics.

For engineers reviewing the BZX84C9V1ET3G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy at 5 mA, thermal resistance (500 °C/W on FR-5), ESD robustness (>16 kV HBM), and compatibility with automated SMT assembly on high-density PCBs.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage under varying load and temperature conditions. Its 9.1 V nominal Zener voltage is specified at I_ZT = 5 mA, with temperature coefficient of +3.8 mV/°C - indicating positive drift above 5 V - and leakage current ≤0.5 µA at 7.3 V reverse bias.

The device features a two-terminal configuration (anode/cathode) with pin 2 unconnected, optimized for low-capacitance operation (130 pF at 0 V, 1 MHz) and fast transient response. Its 225 W peak pulse power rating supports surge immunity per 8 × 20 µs waveform, while Pb-free SOT-23 package meets RoHS and AEC-Q101 requirements when ordered as SZ variant.

Key Specifications

Pinout & Package

SOT-23 (TO-236) plastic surface-mount package, 2.90 × 1.30 × 1.00 mm, void-free thermosetting case with corrosion-resistant finish. Cathode identified by band; pin 2 is internally unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener regulation applications.

Compared with BZX84C9V1ET3G, MMBZ5240BLT1G offers lower dynamic impedance at higher currents but reduced thermal margin on standard FR-5 boards, while BZX84-C9V1,115 matches key parameters and qualifies as a direct second-source option with identical SOT-23 footprint and pinout.

Availability

BZX84C9V1ET3G is available at Aetrix Electronics and suitable for portable power management, automotive sensor biasing, and industrial signal conditioning requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for BZX84C9V1ET3G includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BZX84C9V1ET3G belongs to the BZX84CxxxETxG Zener regulator family, engineered for compact, high-reliability voltage reference and clamping in space- and power-constrained applications.

FAQ

What is the Zener voltage tolerance of BZX84C9V1ET3G at its rated test current?

The BZX84C9V1ET3G has a Zener voltage range of 8.5 V to 9.6 V at I_ZT = 5 mA, corresponding to ±5.5% tolerance around the nominal 9.1 V value. This tolerance is verified per onsemi's August 2024 datasheet revision and applies under TA = 25 °C with pulse testing to minimize self-heating effects. The BZX84C9V1ET3G maintains this specification across its qualified operating temperature range when derated appropriately.

Does BZX84C9V1ET3G have a connected pin 2, and what happens if it is soldered to ground?

No, pin 2 of the BZX84C9V1ET3G is internally unconnected (NC), as confirmed in the mechanical outline and pinout diagram (Style 8) of the datasheet. Soldering pin 2 to ground or any other net creates a parasitic path that may cause unpredictable leakage, increased capacitance, or functional failure. The BZX84C9V1ET3G must be mounted with pin 2 floating - no trace or pad should contact it on the PCB layout.

How does the temperature coefficient of BZX84C9V1ET3G affect its performance in automotive applications?

The BZX84C9V1ET3G exhibits a +3.8 mV/°C temperature coefficient at 5 mA, meaning its Zener voltage increases linearly with junction temperature. In automotive under-hood applications where TJ may reach +150 °C, this results in ~475 mV total drift from 25 °C baseline. Designers using the BZX84C9V1ET3G in such environments must account for this drift in reference-critical circuits - for example, by selecting compensation resistors or verifying system-level accuracy across the full temperature range.

Can BZX84C9V1ET3G replace BZX84C9V1ET1G in existing designs?

Yes, the BZX84C9V1ET3G is a direct replacement for BZX84C9V1ET1G in terms of electrical specifications, thermal behavior, and package dimensions. Both share identical SOT-23 (Case 318) packaging, pinout (1-Anode, 2-NC, 3-Cathode), and Zener characteristics. The only difference is packaging quantity: ET1G ships in 3,000-unit tape-and-reel, while ET3G uses 10,000-unit reels. No PCB or schematic changes are required when substituting BZX84C9V1ET3G for BZX84C9V1ET1G.

What is the maximum reverse leakage current for BZX84C9V1ET3G, and at what voltage is it specified?

The maximum reverse leakage current for BZX84C9V1ET3G is 0.5 µA, specified at V_R = 7.3 V (80% of nominal 9.1 V Zener voltage) and T_A = 25 °C. This value is measured under DC conditions and reflects worst-case off-state conduction. At lower reverse voltages (e.g., 5 V), leakage drops significantly - typically below 10 nA - making the BZX84C9V1ET3G suitable for ultra-low-power monitoring circuits where standby current is critical.